1. Field of the Invention
The present invention relates to a pointing device for manipulating graphical objects displayed on a computer system.
2. Description of the Related Art
A pointing device is a human interface device that generally allows a user to input spatial data to a computer. A pointing device typically interfaces with a graphical user interface (GUI) on an operating system to allow the user to provide the spatial input using physical gestures, such as point, click, and drag. While the most common pointing device is perhaps the mouse, other kinds of pointing devices include a trackball, touchpad, pointing stick, lightpen, joystick, head pointer, eye tracking devices, various kinds of digitizing tablets which use a stylus, and even a special “data glove” that translates the user's movements to computer gestures. Conventional touchpads and pointing sticks are especially common on notebook computers.
Pointing devices have become important for human interaction with a computer. Pointing devices help the computer operator control the movement of a cursor on a computer screen, select graphical objects and menu functions, and so forth, depending upon the application program being used. Many pointing devices, however, such as mice and track balls, require a user to remove one or both hands from a keyboard in order to access and operate them. This results in distraction, loss of time, and the need for space adjacent to the keyboard for their operation.
A track pad is a pointing device that emulates a mouse by sensing the motions of the user's finger over its surface and translating those motions into digital signals. A button below the track pad provides further functionality, such as allowing the user to make selections. Alternatively, the user can tap and double tap on the pad itself. The user can tap and drag on the trackpad in much the same manner as clicking and dragging with a mouse. Although track pads may be built into a keyboard, such as the region below the spacebar of a notebook computer, track pads still require that the user move their hand or hands out of a typing position.
A pointing stick is a pointing device that can desirably be operated while the user's hands remain in the typing position of a keyboard to save time and minimize distraction. A pointing stick and its associated sensor assembly are typically mounted on the sub-key surface of a keyboard such that a stick protrudes between adjacent keys, most commonly centered at the intersection of the “G”, “H” and “B” keys. A nub provided at the top of the stick is typically contoured to provide a comfortable fingertip grip. To emulate mouse button signals, two microswitches and operating buttons are mounted below the space bar (i.e. toward the user), in a position convenient to the thumbs of the typing hands. The user may operate the pointing device from within a conventional typing position, avoiding the distraction, inconvenience, and other problems inherent to using a separate mouse, track ball, or joy stick. A track point requires very little displacement of the hand to move the cursor in any direction desired.
Despite the utility of the various types of conventional pointing devices, there is an ongoing need to improve user efficiency when operating a computer. Even pointing sticks, which allow the hands to remain in a typing position, can be improved in terms of functionality and efficiency. Some application programs require input that is not efficiently accommodated by existing input devices. To provide such input with conventional input devices, an application program frequently requires that the user access a drop-down menu or toolbar in order to temporarily change the operation of the pointing device. For example, in some software applications, selecting a portion of an image for copying requires a user to point and click on an image selection tool icon in the toolbar so that the pointing device may then be used for the specific purpose of selecting/sizing an image. After activating the image selection tool, the application program expects the next pair of clicks to define opposing boundaries of the desired image. Furthermore, before the image may be rotated, the user must point and click on a rotation tool icon in the toolbar in order to accomplish rotation. While this type of process achieves the necessary goal of image selection, it disrupts the continuity and flow otherwise provided with usual operation of the input device.
There remains a need for an improved input device having additional input functionality, more intuitive operation, and greater efficiency. It would be preferable for the improved input device to be conveniently accessible and retain a familiar layout, similar to that of existing pointing devices.